The present invention is particularly applicable, but not necessarily limited to the conveyance on a cushion of fluid of thin-walled cup-shaped circular cylindrical articles of the general type in widespread use for packaging various foodstuffs, including beverages and the like. Such tubular articles or containers are conveniently comprised of a variety of materials which provide for a thin-walled resilient construction, such as, for example, various plastic materials, tin-plated steel, plastic-lined steel, aluminum and the like. Typically, container bodies of aluminum are produced by deep-drawing or a draw and re-draw, or a draw and ironing of an aluminum blank employing modern automatic machines which are capable of production rates presently as high as about 200 container bodies per minute. The preliminarily formed container bodies are trimmed along their open upper edge and thereafter are subjected to various cleaning and coating operations before entering the filling and final sealing operation.
Suitable apparatuses and methods for effecting a high speed, efficient treatment of the surfaces of such container bodies are disclosed in U.S. Pat. Nos. 3,704,685 and 3,748,177, which are owned by the same assignee as the present invention. In accordance with the teachings of the aforementioned United States patents, longitudinally extending guide rods are provided for supporting the container bodies as they are propelled therealong in longitudinally spaced end-to-end relationship and the container bodies are subjected to a plural liquid treatment by the impingement of high pressure liquid solutions against the inner and outer surfaces thereof. A recent technological breakthrough in conveying devices for such container bodies is disclosed in U.S. Pat. No. 3,904,255, which also is assigned to the assignee of the present invention, and provides for a rail having a plurality of cavities therein through which air or fluid is discharged for supporting the container bodies on a cushion of fluid, facilitating their transport and coveyance due to the extremely low frictional characteristics of the fluid cushion. In accordance with the teachings of the aforementioned patent, the rail is stationarily supported and extends for a considerable length and is adapted to accommodate a plurality of the container bodies traveling therealong in spaced relationship while supported on the fluid cushion. The fluid cushion not only provides for a substantially frictionless transport system, but also prevents contact of the surfaces of the container bodies and the supporting structure so that a setting or drying of the treated surfaces can be effected without any marring or damage thereto.
It is conventional practice, after appropriate cleaning and surface conditioning of the container bodies, to subject them to a decorating or printing operation, whereby appropriate indicia are applied to the exterior side wall surfaces thereof. Decorating equipment of the type in widespread commercial use for effecting a high speed decoration of such container bodies is disclosed in U.S. Pat.Nos. 3,220,813; 3,220,833; 3,223,028; 3,227,070; 3,250,213; 3,300,019; 3,339,469; 3,371,603; 3,391,636; 3,616,778; 3,766,851; 3,774,905; 3,855,967 and 3,859,919, the substance of which are incorporated herein by reference. In accordance with the apparatuses disclosed in the aforementioned United States patents, container bodies are sequentially loaded on a plurality of support elements which are mounted on a rotatable carrier and are advanced at circumferentially spaced intervals past decorator printing heads which apply a decorative coating to the side wall surfaces of the undecorated containers. The decorative process may further include the application of a varnish overcoating on the underlying printed surface. In accordance with prior art practice, the decorated container bodies are thereafter transferred to a chain conveyor incorporating pins which extend into the interior of the container bodies, providing support during the course of their travel through a large curing oven to effect a drying and setting of the decorative printing and varnish overcoat. The long length of the conveyor chain, the high temperature to which it is subjected and the serpentine path of travel through the oven, has resulted in frequent breakdowns of the conveyor chain system due to inadequate lubrication, requiring excessive maintenance and repair and costly shutdowns of the line.
It is an objective of the present invention, in accordance with one of its embodiments, to provide a rotary fluid bearing conveyor system for tubular articles, such as container bodies, which is adapted to receive the decorated container bodies from the decorating printer and to effect a drying of the decorative printing and varnish overcoat while supported on a cushion of air, thereby obviating the need of a long pin-type chain conveyor and oven system and its associated problems.